Cranking device



N. W. HART.

CRANKING DEVIICE. APPLICATION nun JUNE 10. ms.

1,330,530. I Patented Feb. 10,1920.

NORTON W. HART, or HART, GEORGIA.

CRANKING DEVICE.

Specification-of Letters Patent.

Patented. Fen-10.1920.

Application filed .Tune 10, 1918. Serial No. 239,208.

i To all whom c't-may concern:

Be it known that I, NORTON W. HART, a citizen of the United States, residing at Hart, in the county of Glascock, State of Georgia, have invented certainnew and useful Improvements in Cranking Devices; and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention is an improvement in internal combustion engines and has particular reference to a cranking device therefor.

An object of the invention is to provide an improved safety cranking device which will permit of the engine shaft being turned without danger to the operator in the event that, in so turning, the engine should back fire.

Another object is to provide a cranking device of this character which is simple in construction, easy to manufacture, readily applicable to engines of known construction and effective in carrying out the purpose for which it is designed.

The inventive idea involved is capable of receiving a variety of mechanical expressions one of which, for the purpose of illustrating the invention, is shown in the accompanying drawing wherein Figure 1 is a front elevation of the cranking device constructed in accordance with the invention.

Fig. 2 is a vertical longitudinal section with the parts in inoperative positions.

Fig. 3 is a similar view with the parts in operative position.

Fig. 4 is a perspective view of the stationary clutch member employed in connection with the invention.

Fig. 5 is a similar view of the movable clutch member.

Referring more particularly to the accompanying drawing, the numeral 10 indicates generally a portion of the frame of an automobile located directly beneath the radiator 11 thereof and in which the usual crank 12 is rotatable and slidable to engage the. inner clutching end 13 thereof with the engine shaft (not shown), the crank being normally maintained in its inoperative position out of engagement with the engine shaft by the usual coil spring 14. This construction is well known in the art and therefore a further description of the sametion consists of a stationary clutch member 15 mounted beneath the radiator 11 and having oppositely disposed and reduced extensions 16 for receiving clamping bolts 17 utilized to attach the clutch member to the frame 10 of the machine. Theclutch member 15 is provided with a-central opening 18 and upon the outer face of the member and surrounding the opening the same is provided with fine ratchet teeth 19' facing to the right for a purpose which will presently apear. I The clutch member 15 is so disposedthat the crank 12 extends centrally through the openihgqlS therein and movable longitudinally of that portion of the crank which extends through said opening 1 8is a second clutch member 20 provided with a reduced hub portion 21 which also surrounds the crank and which is engageable in the opening 18 and rotatable therein. The inner end of the hub portion 21 is provided with an inturned flange 22 which is engaged by the inner end of the spring 1 whereby the same will exert an inward pressure upon the clutch member 20 to maintain the same yieldably in engagement with the clutch member 15. The clutch member 20 is provided at the outer end of the hub portion 21 thereof with an annular shoulder 23 upon which is formed fine ratchet teeth 24 facing to the left and adapted to cooperate with the clutch teeth 19, and the teeth 24 are so disposed as to permit of a rotary clockwise movement of the clutch member 20 but positively prevent any counter-clockwise movement thereof. In this manner it will be apparent that when cranking the engine by the rotation of the crank 12 the movable clutch member 20 will be permitted to rotate freely and the teeth 24 thereof will ride over the teeth 19 but should the crank 12 be thrown in the opposite direction by the engine back firing the teeth 19 and 24 will immediately interlock and rotation of the clutch member 20 in a counter-clockwise direction will be prevented.

In order that the clutch member 20 may be rotated when the engine shaft is cranked, the clutch member 20 is preferably provided upon the outer end thereof with clutch face 25 including a plurality of comparatively large teeth 26, preferably four in number, and each including the inclined surface 27. When the crank 12 is borne inwardly in the usual manner previous to turning the engine shaft, any one of the teeth 26 is adapted to be engaged by a pin or extension 28 formed upon the bend of the crank 12 and projecting in an opposite direction from the handle portion of said crank. After the engagement of the pin or extension 28 with one of the teeth 26, the crank may then be rotated in the usual manner to turn the engine shaft, and in the ordinary operation the crank will be thrown out by the spring 1 1 as soon as the engine is started. In the event that the engine should back fire, the reverse rotation of the crank 12 caused thereby will immediately effect an interlocking relation between the clutch members 15 and 20 and thus prevent any counterclockwise movement of the latter member. The sudden stopping of the clutch member 20 and continued reverse motion of the crank 12 will then cause the pin or extension 28 to ride outwardly upon the inclined surface 27 of the tooth 26 with which said extension is engaged, thus kicking out the crank and disengaging the clutching end 13 thereof from the engine shaft. It will of course be obvious that this operation oc curs almost simultaneously with the back firing of the engine and the crank will therefore immediately be thrown out of operation with the result that the operator will not be subjected to danger or injury by the back firing.

What is claimed is z- In a cranking device for motor engines,

the combination with a crank having an extension on its angle in line with its handle, and a coil spring around its shaft; of a clutch member having a large opening around said shaft and provided in its front face with fine ratchet teeth facmg to the right, and a second clutch member having a hub loosely mounted in said opening, an inturned flange at its inner end against which said spring bears, fine ratchet teeth on its rear face around said hub facing to the left, and coarse ratchet teeth on its front face with interposed surfaces inclining in a direction to kick out the crank when th engine back-fires.

In testimony whereof, I aflix my signature, in the presence of two witnesses.

NORTON /V. HART. Witnesses:

J. C. JARNAGIN, R. H. FOWLER. 

